Performance of the Communication Sub-System of an Intelsat Satellite After 11 Years In-Orbit-A Report

Two of the first three INTELSAT IV series of satellites, INTELSAT IV (F-2) and INTELSAT IV (F-3) were launched on 26 January 1971 and 20 December 1971 respectively. Their useful design life was seven years. However, they continued to provide service for a few years more, until there was not sufficient fuel for station-keeping maneuvers, and were de-orbited in May 1983 and February 1984. This paper will describe the communication sub-system of an INTELSAT IV satellite along with the results of the end-of-life in-orbit test. These results are then compared with the pre-launch data and the in-orbit test data obtained immediately after the launch.